Systems Assurance, Complexity and Emergence: The Need for a Systems Based Approach

The complexity of modern products, systems and processes makes the task to identify, characterise and provide sufficient assurance about the desirable properties a major challenge. Stakeholders also, demand a degree of enhanced confidence about the absence of undesirable properties with a potential to cause harm or loss. The paper develops a framework of seven fundamental facets of performance as an ontology for emergent behavioural properties and a separate framework for the emergent structural properties of complex systems. The emergent behavioural aspects are explored and we develop a systems framework for assurance based on an Assessment and Management paradigm each comprising a number of principles and processes. The key argument advanced is that in the face of complexity and incessant change, enhanced confidence in the achievement of desirable and avoidance of undesirable properties requires a systems approach empowered by suitable modelling and relevant diagnostic tools explaining the nature of emergent properties. The principal focus of this paper is on safety, security and sustainability emergent behavioural (performance) aspects of complex products, systems and processes